刘华

时间、原因等状语从句可以转换成分词作状语，但这种转换是有条件的，也可以總结出一些规律。

一、基本规则，也是最重要的规则：从句的主语与主句的主语必须一致，从句变成分词作状语，而主句不变。如：

1. They did not go to the party because they had a lot of work to do.

此句because 引导原因状语从句，由于从句的主语与主句的主语都是they，可以把从句中的because和they去掉，把had变成having，即成现在分词短语作原因状语：

Having a lot of work to do，they did not go to the party.

2. When ice is heated， it will be changed into water.

此句when 引导时间状语从句，由于从句的主语与主句的主语都是ice， 可以把从句中的主语和be 动词去掉，或者连词when 也可以去掉，改成过去分词heated作状语。

When heated， ice will be changed into water.

或者Heated， ice will be changed into water.

二、从句的主语如果与主句的主语之间逻辑上是主谓关系，动作为正在进行或完成，则转换成现在分词;如果是被动关系，则转换成过去分词。

1. When he heard a cry for help，he rushed out.

从句中，he 与hear是主动关系，表示“他听见”，可变成现在分词作时间状语，或者保留连词。

Hearing a cry for help，he rushed out.

When hearing a cry for help， he rushed out.

2. After the girl learned some simple Chinese， she was able to communicate with us.

after引导原因状语从句，从句主语与主句主语一致，learn some simple Chinese 与be able to communicate with us 之间有先后顺序，则句子可以转换为：

After learning some simple Chinese， she was able to communicate with us. （用after 表示动作先后）

或 Having learned some simple Chinese， she was able to communicate with us. （用having done 表示动作先后）

3. Because he hadnt finished his homework， he didnt watch the football match.

because 引导原因状语从句，从句主语与主句主语一致，用现在分词表示主动，但从句的动作在主句动作之前，分词要用完成式，则句子可以转化为：

Not having finished his homework， he didnt watch the football match. （注意：not 放在分词的前面）

4. When he was asked by the teacher， he answered politely.

when 引导的从句中，he和ask是被动关系，则变成过去分词作时间状语，或保留连词。

Asked by the teacher， he answered politely.

或 When asked by the teacher， he answered politely.

5. When the tall building was attacked by terrorists， the tall building collapsed.

when 引导时间状语从句，从句主语与主句主语一致。根据句意;大楼因为受到恐怖分子的袭击而倒塌，从句动作先于主语动作，则句子可转换为：

Having been attacked by terrorists， the tall building collapsed.

三、如果从句的主语与主句的主语不一致，该怎么办？……